USDA & Thermometers - verifying the calibration

We have a liquid in glass thermometer that has not been calibrated since 2010, but we have been using NIST-traceable thermometers on a daily basis and checking them each day using an ice bath. My question is, do we need to have the liquid in glass if we are using NIST-traceable thermometers to take temperatures? It seems very redundant. It seems that we originally got the liquid in glass thermometer for USDA. Does anyone know what other methods of verifying the calibration on thermometers used in production?

What are you checking the NIST thermometers against?  If you check them against the liquid in glass, that has to calibrated to ensure its accuracy.

EDITED to add: I missed the ice bath--sorry~!  But you would want something documented wouldn't you? And checking against the liquid in glass would be easier and faster than an ice bath.

Setanta

So you could check the thermocouple with liquid in glass at room temperature? as opposed to using both in an ice bath?

I still think the LIG thermometer needs be calibrated. 

We calibrate our NIST thermometers weekly in an ice bath and compare with the calibration standard thermeter. Annually the calibrating thermometer goes out for calibration and certification.

Sorry to muddy the waters.  I should not multitask like this!

USDA is satisfied that we are verifying that our NIST thermometers are calibrated daily using a calibration block (hot and cold temperatures). The calibration block is sent out annually for calibration and certification.

Dear Lacey -

    You have to have something (certified thermometer or EHam's calibration block) that is sent out yearly to verify its accuracy. That is your certified device that you then use to check the rest of your thermometers against to verify their continuing accuracy. You obviously can send all your in-use thermometers out for NIST accuracy checks, but that can get expensive...